522 DISCOVERY REPORTS 



and four concentrations of Limacina are conspicuous. The Copepoda present a series of 

 wave-like fluctuations along the whole course of the records. During the night of 

 February io-n there is a general increase in the Copepoda, reaching a maximum about 

 midnight; whilst this may well be due to vertical migration, there is a well-marked 

 fluctuation superimposed upon this general increase. The densest concentration of 

 Copepoda occurred at 1700 o'clock on the 10th. During the night of February 12-13 the 

 numbers of Copepoda were nothing like so high as those for the ioth-nth, but the 

 young euphausians were as well represented. Chaetognatha, Amphipoda and larger 

 Euphausiacea were taken in small numbers. 



Records ii and 12 



Dates: 18-19. ii. 26. 



Times: 23 10-1330 and 1500-2000. 



Position: 51° 57' S, 32 31' W to 53 21' S, 34 53' W. 



Distance by ship's log: 109-4 miles. 



These two records form a continuous series in a line approaching South Georgia from 

 the north-east, broken only by an interval in time when the ship stopped for soundings 

 ( 1 330-1 500). The records show (Fig. 9) a dense belt of the diatom Thalassiothrix ant- 



5157 S 

 32°3l'W 



THALASSIOTHRIX ANTARCTICA 



SHIP 



STOPPED 



FOR SOUNDINGS 



COPEPODA 



30i 



oi 



200 



150 



100- 



50 







EUPHAUSIAN LARVAE 



L MUCIN A 



^ tT g mTl3l4l5l6l7lBl9 1 10 I II I IZl 131 I4ll5l 16 I I7l 18 I l9l20l2lla|g3la4lzSlZ6l27l2al29l30l3ll32l33!34l3SI36l37l3BI39|40|4) I42I43I^45|46|47|46| 



40 



50 



90 



110 



HOUR 2310 



02 03 



04 05 



07 



oa 09 



13 13^0 



15 00 



Fig. 9. Variations in the numbers of the predominant plankton organisms on Records 1 1 and 1 2 ; the division 

 between these records where the ship stopped for soundings is indicated by the vertical broken line. 



arctica stretching for 75 miles and followed by a small but almost equally dense patch 

 some 12 miles farther on. An interesting feature of the record is the dense concentration 

 of the larval Euphausiacea which occurred in the gap between the two patches of phyto- 

 plankton. The significance of the inverse correlation between the phyto- and the zoo- 

 plankton has been discussed at length by the author recently (in Hardy and Gunther, 

 1935). In this record it is impossible to decide whether the concentration of the 

 euphausians is to be attributed to an exclusive influence of the phytoplankton or 



